Pyrazolo[1,5-a] triazin-4-amine is a scaffold previously used in medicinal chemistry and derivatives thereof are known for their potent utility as corticotropin-releasing factor receptor-1 (CRF1) antagonists which may be potential anxiolytic and antidepressant drugs (for example Gilligan et al (J. Med. Chem. 2009, 52, 3073-3083). Pexacerfont is a pyrazolo[1,5-a]triazin-4-amine drug developed by Bristol-Myers Squibb and acts as a CRF-1 antagonist which have been tested clinically. The scaffold has also been described as present in cyclin-dependent kinase inhibitors (WO2013128029), casein kinase inhibitors and DYRK1A kinase inhibitors (WO2010103486) useful for treatment of various diseases. The scaffold has further been described as present in cannabinoid 1 receptor antagonists (J. Pharm. Exp. Ther. (2010), 335(1), 103-113).
Similar scaffolds have been described as present in phosphatidylinositol 4-kinase (PI4K) inhibitors (McLeod et al (ACS Med. Chem. Lett. 2013, 4(7), 585-589) and van der Schaar et al (Antimicrobial Agents Chemother. 2013, 57(10), 4971-4981) and inhibitors of PI4K have shown to be potent antivirals (Bianco et al, PLoS Pathogens, 2012, 8(3), 1-17; LaMarche et al, Antimicr. Agents and Chemother. 2012, 56(10), 5149-5156; Décor et al, Bioorg Med Chem Lett. 2013, 23, 3841-7).
Pyrazolo[1,5-a] triazin-4-amine have been described as PI4K inhibitors with antiviral potency in Mejdrova et al (J. Med. Chem., 2015, 58 (9), pp 3767-3793).
There still remains a need for new therapeutically active compounds.